New Study Finds Washing Produce May Not Be Enough to Remove Pesticide Residue

Washing produce may not be enough to remove pesticide residue.

A new study out of China’s Anhui Agricultural, Wuyi, and Wuhan Universities published in Nano Letters finds pesticide residue moves beyond the surface of fruits and vegetables. Making even the most rigorous of washing protocols ineffective.

The use of pesticides is a common practice in agricultural processes. These pesticides and chemicals are intended to kill or prevent the spread of pests and plant illnesses. This helps increase yields and reduces risks to crops.

But at a cost.

A recent Consumer Reports study identified significant risks associated with commonly consumed fruits and vegetables.

Consumer Reports Study Finds Significant Risks in 20% of Foods Examined

Popular foods and vegetables such as bell peppers, blueberries, potatoes, and strawberries were examined for amounts of pesticides and compared to safe levels for a four-year-old.

Imported green beans, especially those from Mexico, were found to have residues for a pesticide outlawed in the United States for over a decade.

Overall, pesticides posed significant risks in 20% of the foods examined in the study.

Some of these hazardous pesticides include organophosphates, chemicals known to cause “neurodevelopmental effects.” Carbamate insecticides have been heavily researched for their “toxic effects such as interfering with the reproductive systems and fetal development.”

Shouldn’t Washing Produce Eliminate the Risk?

You may be thinking, “shouldn’t washing produce eliminate the risk of pesticide residues?”

In theory, it sounds right. Something applied topically to plants should be removed topically.

Unfortunately, that is not the case.

A paper published in the American Chemical Society’s journal, Nano Letters, was originally designed to promote a novel technology in detecting pesticide residues in food. But it showed even more.

Pesticides do not stay on the surface.

This paper, Cellulose Surface Nanoengineering for Visualizing Food Safety, found a distribution of pesticides within the apple peel. The authors explain, “Notably, the distribution of pesticides in the apple peel and pulp layers is visualized through Raman imaging, confirming that the pesticides penetrate the peel layer into the pulp layer (~30 um depth).”

If Washing Produce Cannot Remove Pesticides, What Can You Do Instead?

The authors posit an alternative for safely consuming fruits and vegetables potentially containing pesticide residues. And it is a simple solution.

Peeling.

Yes. Peeling.

For foods with a skin that can easily be peeled, pulling out your trusty vegetable peeler could be the answer you have been looking for.

“We believe that the peeling operation can effectively avoid the hazards of pesticides in the fruit’s epidermis and near-epidermal pulp, thereby reducing the probability of ingesting pesticides,” the researchers wrote in their report.

Unfortunately, this cannot be done for all fruits and vegetables. I have never attempted to “peel” kale or mustard greens. But I can imagine this is an impossible task.

This could, however, be a solution for foods like watermelon and celery. Even for fruits like peaches, pears, and apples.

What About Fruits and Vegetables That Cannot Be Reasonably Peeled?

For those fruits and vegetables that cannot be reasonably peeled, limiting the number of servings in a day can reduce your overall risk.

Fortunately, Consumer Reports identified categories to help consumers limit the number of servings of certain higher risk produce.

High Risk Produce

Higher risk produce was broken down into very high risk (a limit of ½ serving per day) and high risk (a limit of one serving per day)

Very high-risk foods include:

• Bell pepper
• Blueberries
• Imported celery
• Imported collard greens
• Imported strawberries

High-risk foods include:

• Imported bell peppers
• Imported blueberries
• Green beans
• Hot peppers
• Kale
• Mustard greens
• Spinach (canned/frozen)
• Frozen Strawberries
• Watermelon

Moderate Risk Produce

Moderate Risk produce should have a limit of three servings per day.

Moderate-risk foods include:

• Apples
• Imported basil
• Imported cauliflower
• Celery
• Collard greens
• Imported cucumber
• Grapes
• Peaches
• Pears
• Radish
• Imported snap peas
• Domestic strawberries
• Tomato

Low Risk Foods

Low risk foods and very low risk foods such as kiwi, lettuces, mushrooms, onion, and others allow 10 or more servings a day and pose no significant health concern.

At least based on current information. Risk factors are an evolving process.

Washing Produce Is Still a Good Idea

Even if you plan to peel produce (where peeling is possible), washing produce is still a recommended practice. Reducing risk of foodborne pathogens such as Salmonella, Listeria, or E. coli are additional concerns when consuming raw produce.

The U.S. Food and Drug Administration (FDA) recommends a few simple tips to be sure to clean your produce safely and effectively.

Inspect Produce

Select produce items that aren’t bruised or damaged. Compromised surfaces of the skin or rind can allow harmful pathogens or pesticides to enter the flesh.

Keep Pre-cut Items Cold

Only select pre-cut items like bags of lettuce, watermelon slices, or vegetable trays that are refrigerated, on ice, or both. Get these items in your home refrigerator as soon as possible.

Wash Your Hands

Before and after preparing fresh produce, be sure to wash your hands. This includes washing produce before you eat it. Use soap and warm water and spend at least 20 seconds on the task.

Rinse Produce BEFORE You Peel It

For produce that you can peel, wash or rinse (as appropriate) prior to peeling. This helps prevent bacteria from transferring to the knife onto the fruit or vegetable flesh.

Gently Rub Produce Under Running Water

To thoroughly clean your produce, you will want to gently rub it while holding the item under plain running water. Soap or produce wash are not necessary.

Use a Vegetable Brush

A vegetable brush is an effective tool for firm produce like melons and cucumbers. Niche manufacturers also make tools for soft items like mushrooms.

Dry After Washing Produce

Use a clean cloth or paper towel to dry produce after you wash it. This helps to further reduce any bacterial or pesticide contamination present.

Remove Outermost Leaves

Headed produce like lettuce and cabbage can be problematic to clean. This is because the leaves grow tightly as the plant matures. For these items, remove the outermost leaves and wash the first layer of tightly held ones.

Don’t Be Afraid to Eat Your Veggies

It may sound scary to hear how much potential contamination is found on the foods we regularly consume. But that should not deter you from eating your veggies.

Opt for organic or grown with organic practices when possible. Peel fruits and vegetables that can be peeled. Thoroughly wash produce that can’t be peeled. And pay attention to recommended serving limits for those in the higher risk categories.

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By: Heather Van Tassell (contributing writer, non-lawyer)